松原龙华松花江特大桥主桥悬臂浇注中临时水准点的复测

阐述了松原龙华松花江特大桥半刚构连续箱梁施工中临时水准点的设置与复测。主桥箱梁在悬臂施工过程中，必须设置高程控制观测点和施工临时水准点，以此作为全桥高程控制的基准，控制悬臂浇注时梁块的标高，确保全桥合拢后各点标高值符合设计要求。实践证明，龙华松花江特大桥成桥后的线形和合拢精度均达到施工规范的要求。     

肇松松花江特大桥高程监控中温度影响的探讨

在悬臂浇筑法施工中，如何控制主梁的标高及其变化，是施工监控所要解决的首要问题之一。而影响悬臂浇筑法施工的因素众多，有梁体自重、张拉力、混凝土的收缩、徐变、活载和温度变化引起标高变化。在肇松松花江特大桥施工控制实践中，温度变化引起悬臂箱梁标高不断发生变化，主要是竖向温度场的变化引起各悬浇块标高的变化，即由日照温度变化引起的变形。此项变形值在施工高程控制中以实测的温度变形速度计入。     

预应力混凝土半刚构连续箱梁桥施工中的桥面高程控制

结合吉林省松原市龙华松花江特大桥的施工实践，对大跨度半刚构——连续梁桥的挂篮悬臂浇筑施工过程中产生挠度的因素进行分析和总结，分析了影响该桥施工控制的主要因素和关键技术，论述桥面高程控制的理论和方法，通过设置合理的预拱度达到对成桥线形的控制。并采用了离散性线性系统的卡尔曼滤波来估算分析现场施工中的标高误差，调整立模标高，使成桥后线形满足设计要求。     

陶赖昭松花江特大桥悬臂浇筑阶段高程控制

陶赖昭大桥的施工采用悬臂浇筑法施工。施工高程控制 ,即悬臂段标高控制是保证施工质量以及桥梁结构体系顺利合拢的关键。本文综合考虑影响施工高程控制的相关因素 ,确立了悬臂浇筑各阶段的立模标高 ,并对结果进行了修正。     

半刚构-连续箱梁剪力滞效应的三杆比拟法

采用三杆比拟杆法推导薄壁箱形截面梁的剪力滞效应计算公式，用其计算龙华松花江大桥施工阶段的悬臂状态、合拢后自重及二期恒载等工况的剪力滞系数，分析该桥的剪力滞效应。     

大跨预应力混凝土连续刚构桥承载能力试验与评定

为了判定连续刚构桥梁在试验荷载作用下的实际工作性能和承载能力,评价桥梁的施工质量,本文以松原龙华松花江特大桥为实例,运用有限元法对该桥进行理论分析,以此为基础对该桥竣工阶段进行静载试验,对控制截面的挠度和应变进行测试分析。依据试验结果,运用交通部公路科学研究院颁布的《公路桥梁承载能力评定规程》中的承载力评定方法对该桥进行承载能力评定。评定结果说明该桥承载能力满足设计要求,主梁处于良好的弹性工作状态,可以正常使用。同时根据分析时发现的问题提出该种结构在设计和施工上应该注意的问题,为以后该种桥型的建设提供借鉴。     

陶赖昭松花江特大桥施工控制

本论述陶赖昭松花江特大桥控制的体系、方法、内容及实施过程，并分析了影响施工控制的主要因素和关键技术。有效地调整了桥梁的内力和线形，为提高桥梁施工质量和安全可靠提供科学保证。可供同类桥梁的施工控制试用和参考。     

吉林九站松花江特大桥模型与实桥车辆振动试验分析

介绍了吉林九站松花江特大桥的模型和实桥车辆振动试验情况。数据表明 ,该桥在正常使用荷载的作用下 ,箱梁处在正常的弹性范围内工作 ,安全储备较大 ,安全可靠。     

松原龙华松花江特大桥悬浇施工风载分析

采用Ansys程序对龙华松花江特大桥施工悬浇阶段刚构桥墩进行风荷载内力分析,保证其结构在自重和静阵风荷载下可以安全施工.     

松花江公路特大桥南岸主塔钻孔桩成孔工艺

本文主要介绍哈尔滨绕城公路西段松花江特大桥主桥主塔桩径 2 0m、桩长 70m的钻孔桩施工技术。     

Leaf gas exchange in the frankincense tree (Boswellia papyrifera) of African dry woodlands

A conceptual model was tested for explaining environmental and physiological effects on leaf gas exchange in the deciduous dry tropical woodland tree Boswellia papyrifera (Del.) Hochst. For this species we aimed at (i) understanding diurnal patterns in leaf gas exchange, (ii) exploring cause-effect relationships among external environment, internal physiology and leaf gas exchange, and (iii) exploring site differences in leaf gas exchange in response to environmental variables. Diurnal courses in gas exchange, underlying physiological traits and environmental variables were measured for 90 trees on consecutive days at two contrasting areas, one at high and the other at low altitude. Assimilation was highest in the morning and slightly decreased during the day. In contrast, transpiration increased from early morning to midday, mainly in response to an increasing vapor pressure deficit (VPD) and gradual stomatal closure. The leaf water potential varied relatively little and did not influence gas exchange during the measurement period. Our results suggest that the same cause-effect relationships function at contrasting areas. However, leaves at the higher altitude had higher photosynthetic capacity, reflecting acclimation to higher light levels. Trees at both areas nevertheless achieved similar leaf assimilation rates since assimilation was down-regulated by stomatal closure due to the higher VPD at the higher altitude, while it became more light limited at the lower altitude. Gas exchange was thus limited by a high VPD or low light levels during the wet season, despite the ability of the species to acclimate to different conditions.     

甘肃河西地区土地沙化治理的对策及治沙造林技术

本文主要从河西地区沙漠的危害性出发,把防沙治沙作为西部大开发生态环境建设的主题,融传统经验与现代技术把防沙治沙提到前所未有的高度,加速了科技成果的推广应用,改善了沙区人民的生活环境。     

Regional vegetation management standards for commercial Eucalyptus plantations in South Africa

During the 1990s a number of trials were implemented in the summer-rainfall region of South Africa to determine both the short- and long-term impacts of competing vegetation on eucalypt growth. Trial sites were selected across different physiographic regions such that a range of altitudinal, climatic and environmental gradients were represented. Although the understanding gained from these trials allowed for the development of vegetation management standards, their operational and economic viability needed to be tested on a commercial basis. Five eucalypt trials were thus initiated to test the applicability of these standards when utilised on a commercial scale. One of the trials was situated at a lower-altitude site (65 m above sea level [asl]), two at mid-altitude sites (878 and 1 262 m asl), and two at higher-altitude sites (1 469 and 1 590 m asl). Several vegetation management treatments developed to suit the predicted vegetation load at each site were implemented and varied according to either weeding intensity (high, moderate and low), or the area around the tree that was kept free of vegetation (no vegetation control, a row weeding and complete vegetation control). Following tree crown closure at each trial, tree growth was linked to the level of vegetation management in each treatment and its associated total cost up to canopy closure, allowing for the development of different cost-benefit comparisons. The intensity of vegetation management required to produce significant growth benefits decreased with increasing altitude, as did the area that needed to be kept free from competing vegetation. In contrast to the two higher-altitude sites, where tree growth did not benefit from vegetation management, a significant increase in tree growth occurred for the high- and moderate-intensity vegetation management operations at the three mid- and lower-altitude sites. Besides demonstrating the commercial applicability of research results, this series of trials has shown that site-dependent vegetation management is viable on a commercial scale and will allow the South African forest industry to adjust their weed control budgets on a regional basis (linked to altitude).     

挡土墙填土设计方案

在山坡地建筑或在深基础施工中,常用挡土墙阻挡土和维持地面高差;在公路、铁路建设中,也常常需要沿挖方或填土边沿设置挡土墙或护坡.本文介绍了几种挡土墙填土方案.     

辽西地区华北落叶松造林立地条件选择的研究

通过对不同立地类型上营造的华北落叶松成活率生长情况调查研究,结果表明:不同的海拔高度、坡向和土层厚度对华北落叶松的生长有较大影响,选择海拔在800 m以上,基岩母质以微酸性的花岗岩、片麻岩、基性岩,坡向以北坡等立地营造华北落叶松,将有较大的成活率和保存率,林木生长量大。     

文冠果基因种质资源收集圃营建及幼树生长量评价

本文阐述建立文冠果优良基因收集圃过程和步骤,并对圃内三类群体26个家系(混系)2 a生生长量进行评价,结果表明:造林后,优树群体无论是当年成活率还是第2 a保存率都明显优于高海拔群体和普通群体。在树高生长量方面,优树群体超过普通群体98.3%、超过高海拔群体39.4%;在地径生长量方面,优树群体超过普通群体35.6%、超过高海拔群体17.0%。三类群体在树高和地径生长量上优劣顺序为优树群体高海拔群体普通群体。在树高和地径生长量上表现最好3个家系为Y6、Y4和Y5。     

西南桦林相思拟木蠹蛾危害调查

对广西百色市老山林场、右江区西南桦林相思拟木蠹蛾Lepidarbela baibarana(Matsumura)不同海拔高度危害程度、人工修枝对危害程度影响、树干不同高度害虫分布情况等进行调查。结果表明,相思拟木蠹蛾主要危害低海拔西南桦,危害程度随着海拔的上升而下降。幼虫侵入期人工修枝会加重相思拟木蠹蛾危害。害虫对树干高度有选择性,树干4.1～6.0 m受害最重。局部地区的西南桦受相思拟木蠹蛾危害严重,应加强该虫监测防治技术研究。